Tooth for earth digging devices



July 29, 1941.

B. COFFMAN TOOTH FOR EARTH DIGGING DEVICES Filed Sept. 26, 1940 Zi /259w:

ZZ/fman Patented July 29, 1941 UNgiTED STATES PATENT QFFICE TOOTH FOR EARTH DIGGING DEVICES Berttram C'oifman, Downey, Calif.

Application September 26, 1940, Serial No. 358,536

3 Claims.

This invention relates to a tooth for use in connection with earth digging devices such as trenching machines, shovels and the like, and it is an object of the invention to provide a tooth of this kind comprising a construction and assembly whereby may be used a cutting point which can be readily and quickly applied thus materially prolonging the period of use of the tooth as a unit.

In connection with a tooth of the general character as comprised in the present invention, the cutting point thereof quickly becomes worn and often breaks thus rendering the tooth unfit for further use until it has been re-sharpened. The present invention has for an object to provide a tooth of this kind wherein the cutting point comprises a separate blade which may be detachably applied to the tooth but effectively maintained in desired working position.

It is also an object of the invention to provide a tooth of this kind wherein the cutting point constitutes a separate member mounted upon the tooth in a manner whereby the point can be extended within a certain range as desired so as to compensate for the wear of the point either as a result of use or sharpening.

The invention consists in the details of construction and in the combination and arrangement of the several parts of my improved tooth whereby certain important advantages are attained and the device rendered simpler, less expensive and otherwise more convenient and advantageous for use, as will be hereinafter more fully set forth.

The novel features of my invention will hereinafter be definitely claimed.

In order that my invention may be the better understood, I will now proceed to describe the same with reference to the accompanying drawing, wherein:

Figure 1 is a view in perspective of a tooth constructed in accordance with an embodiment of my invention;

Figure 2 is a sectional view taken substantially on the line 2--2 of Figure 1;

Figure 3 is a sectional view taken substantially on the line 33 of Figure 2;

Figure 4 is a view in bottom plan of the outer end portion. of the tooth proper with .a part broken away;

Figure 5 is a view in bottom plan of the separable point blade as herein embodied.

As disclosed in the accompanying drawing, my improved tooth I is of desired dimensions and has its outer or working end beveled, as atZ.

The tooth I, as herein disclosed, is integrally formed with and is in continuation of an elongated shank 3. The tooth l and shank 3 are in desired angular relation and the shank 3 is provided at a point spaced therealong with the openings 4 whereby it may be securely anchored in desired position upon a trenching machine, excavator, or other earth digging apparatus or devices. While my invention may be employed with many different types of earth digging devices or apparatus, it is to be stated that it is particularly intended for use with trenching machines.

Overlying the front face of the tooth l is a cutting point blade 6 of a length greater than the length of the tooth I so that the forward cutting end thereof will extend a predetermined distance in advance of the adjacent beveled end 2 of the tooth I. This blade 6 is formed preferably of steel and the cutting extremity thereof can be readily sharpened as desired.

The point blade 6 is detachable with respect to the tooth l and the rear end portion of the blade 6 at its transverse center has pressed therefrom a knob 0r protuberance 1 which fits selectively and snugly within one of the longitudinally disposed depressions 8 formed in the front face of the tooth l and spaced apart lengthwise thereof. The fitting of the knob or protuberance 1 within a depression 8 serves to effectively hold the blade against endwise movement in a selected adjusted position.

The applied blade 6 is held to the tooth l by the sleeve 9 which snugly slides over the assembled tooth l and blade 6 as is particularly illustrated in Figures 1 and 2 of the drawing. This sleeve 9 is of a design to closely approximate the form of the tooth I.

The side walls a of the sleeve 9 closely adjacent to the forward or outer wall b of the sleeve are provided with the aligned openings I!) which register with a groove ll. extending transversely across the rear face of the tooth l in relatively close proximity to its inner end. Removably insertible through these openings I0 and within the groove H is a holding pin [2 whereby the sleeve 9 is effectively held in applied position.

To further assure the desired maintenance of the sleeve 9 in position, the side faces of the tooth l closely adjacent to their inner ends are provided with transversely aligned recesses [4 into which the adjacent portions of the side walls a of the applied sleeve 9 may be pressed.

As hereinbefore described it is believed to be obvious that my improved tooth as herein disclosed is one whereby its period of use may be materially prolonged due to the convenience with which the point blade 6 can be applied or removed as the exigencies of practice may require. It is also to be stated that my improved tooth is adapted to be applied to an excavator bucket B of a well known type of wheel trench digger.

From the foregoing description it is thought to be obvious that a tooth constructed in accordance with my invention is particularly well adapted for use by reason of the convenience and facility with which it may be assembled and operated, and it will also be obvious that my invention is susceptible of some change and modification without departing from the principles and spirit thereof and for this reason I do not wish to be understood as limiting myself to the precise arrangement and formation of the several parts herein shown in carrying out my invention in practice except as hereinafter claimed.

I claim:

1. An earth digging tooth, means for securing said tooth in working position, the front face of the tooth being provided therealong with spaced depressions, a separable point blade disposed along the front face of the tooth and having a part fitting selectively within one of the depressions of the tooth, and a sleeve surrounding the tooth and the blade for holding the blade in applied position.

2. An earth digging tooth, means for securing said tooth in working position, the front face of the tooth being provided therealong with spaced depressions, a separable point blade disposed along the front face of the tooth and having a part fitting selectively within one of the depressions of the tooth, a sleeve surrounding the tooth and the blade for holding the blade in applied position, and means for holding the sleeve in place.

3. An earth digging tooth, means for securing said tooth in working position, the front face of the tooth being provided therealong with spaced depressions, a separable point blade disposed along the front face of the tooth and having a part fitting selectively within one of the depressions of the tooth, a sleeve surrounding the tooth and the blade for holding the blade in applied position, and means for holding the sleeve in place, said means being removable.

BERT'I'RAM COFFMAN. 

